ABSTRACT This collaborative R01 combines the expertise of the Department of Psychiatry, Johns Hopkins Bayview Medical Center and the Department of Psychiatry at Weill Cornell Medical College in the areas of depression and MCI research. We propose to test whether Problem Adaptation Therapy for MCI patients (PATH-MCI), a novel psychosocial intervention designed to reduce depression in MCI patients, has better cognitive, functional, and affective outcomes compared to Supportive Therapy for Cognitively Impaired Older Adults (ST-CI) in older adults with Mild Cognitive Impairment (MCI) and major or minor depression. Problem Adaptation Therapy (PATH) is a novel psychosocial intervention designed to reduce depression and disability in older adults with major depression, wide range of cognitive impairment (from mild cognitive deficits to moderate dementia), and disability. PATH aims to reduce depression by improving emotion regulation. To achieve its goals of emotion regulation, PATH utilizes a simplified problem solving approach, employs environmental adaptations to bypass cognitive and functional limitations, and involves a significant other when appropriate. Preliminary data show that PATH significantly improves cognitive, functional and affective outcomes in older adults with major depression and mild cognitive deficits compared to another depression treatment, Supportive Therapy for Cognitively Impaired Older Adults (ST-CI). We streamlined the PATH manual focusing only on MCI patients (PATH-MCI) and modify it to increase its treatment effects and reduce costs by: a) providing in-office instead of home-delivered sessions; b) utilizing individualized techniques, such as the MindMe tablet app, customized CDs, or step-by-step written plan, to help patients regulate their emotions between sessions; and c) incorporating monthly booster sessions. Based on our power analysis, we will randomize 80 older adults (60-85 years old) with MCI and major or minor depression to 15 in-office sessions (12 in first 12 weeks and 3 booster monthly sessions afterwards) of PATH- MCI vs. ST-CI in both sites. Both sites are major academic medical institutions that have shown evidence of feasibility of recruitment, randomization, retention, and assessment procedures. Weill Cornell researchers have conducted other NIH and Alzheimer's Association funded investigations that include administration of PATH in older adults with wide range of cognitive deficits (from mild cognitive deficits to moderate dementia). Assessments will be performed at baseline, 6 (no cognitive outcomes), 12, 24, 36 (no cognitive outcomes) and 52 weeks by research assistants unaware of the study hypotheses and the participant's randomization status. In each site, certified mental health clinician will administer PATH-MCI and ST-CI.